Drug & supplement interaction

Caprylic Acid + Trimethaphan

Trimethaphan brand name: Arfonad.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Caprylic Acid has a moderate interaction with Trimethaphan. Theoretically, caprylic acid might increase the risk of hypotension when used with antihypertensive drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Caprylic Acid and Trimethaphan

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Trimethaphan

Trimethaphan falls under ANTIHYPERTENSIVE DRUGS — the group Caprylic Acid interacts with.

Theoretically, caprylic acid might increase the risk of hypotension when used with antihypertensive drugs.
Animal research suggests that caprylic acid might have positive inotropic effects, resulting in reduced arterial pressure and vascular resistance and increased cardiac output.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Trimethaphan (Arfonad) is a strong blood pressure lowering medicine given through the vein, usually in a hospital to bring high blood pressure down quickly. Because it already drops pressure powerfully, anything else that nudges blood pressure lower deserves attention.

Here's the connection: in animal studies, caprylic acid seemed to relax blood vessels and lower arterial pressure on its own. So in theory, stacking it on top of trimethaphan could add up and make your pressure fall too far. That might show up as dizziness, lightheadedness, blurred vision, or fainting when you stand. Keep in mind this is theoretical, based on lab data, not proven in people. Still, since trimethaphan is so potent, mention any supplements to your care team before they're used together.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kristev A, Mitkov D, Lukanov Y, Chapkynov P. The effect of octanoic fatty acid on the cardiovascular system of the guinea pig. Cor Vasa 1989;31(4):321-7.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Caprylic Acid Also Interacts With Other Medications

Caprylic Acid has 261 moderate known drug interactions in our database — the Trimethaphan one above is one of them. If you take anything else, check it against the full list below.

Moderate 261 No known interaction 2,569 (incl. Trimethaphan)
Taking anything else?

Check Another of Your Medications Against Caprylic Acid

Covers the 2,830 medications we’ve checked against Caprylic Acid. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Trimethaphan

This page covers Caprylic Acid only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Trimethaphan page lists 136 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Tyramine (major) and Adrafinil (moderate).

By severity: 4 major · 111 moderate · 21 minor.

From our pharmacist’s overview on the Trimethaphan page

“Trimethaphan (Arfonad) is given by IV to drop blood pressure quickly, often during surgery or a hypertensive emergency, so I would read this list with real vigilance rather than a shrug. Of the 136 flagged ingredients, nearly all act on blood pressure itself, some adding to the drug's lowering effect and others, tyramine being the clea…”

Reviewed by 2 · Jul 18, 2026

Open the Trimethaphan interaction page

One more smart check

Taking Caprylic Acid as Part of a Dietary Supplement Product? Check It for Interactions

We hold 514 real supplement products containing Caprylic Acid, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Caprylic Acid. Your product may carry other ingredients that interact with Trimethaphan too, on top of Caprylic Acid — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Caprylic Acid and Trimethaphan Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Caprylic Acid
Top 25%

#320 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Trimethaphan
Top 10%

#145 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Caprylic Acid

What is Caprylic Acid?

Caprylic Acid
  • Candida and yeast overgrowth
  • Gut health support
  • Antimicrobial
  • Digestive health
  • Part of ketogenic diets

Caprylic acid is a medium-chain fatty acid found in coconut oil and palm kernel oil that is popularly used for yeast overgrowth and gut health. While laboratory studies show it has antimicrobial activity, strong human evidence for most supplement claims is limited. It is generally considered safe in food amounts, but talk with your pharmacist or doctor before using concentrated supplements.

Read the full Caprylic Acid monograph & all interactions
Keep checking

Other Drugs & Caprylic Acid

Browse every other medication we’ve checked against Caprylic Acid — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
261Moderate
0Minor
2,568No known interaction
261 Moderate 2,568 No interaction
Moderate

261 interactions

Showing 60 of 261 moderate interactions — see all 261 on the Caprylic Acid page.

No interaction 2,568 drugs checked — show the list

We also checked Caprylic Acid against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,568 medications checked with no known interaction — see the full Caprylic Acid list.

See the full Caprylic Acid interactions page
See every supplement checked against Trimethaphan, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Caprylic Acid monograph › Uses, safety, and every drug interaction in one place Trimethaphan supplement interactions › Every supplement checked against Trimethaphan, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Caprylic Acid and Trimethaphan Together: Common Questions

Can you take Caprylic Acid with Trimethaphan?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Caprylic Acid and Trimethaphan interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Trimethaphan and Caprylic Acid?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.